Clutch for a brace



p 2, 1958 P. s. MORGAN 2,850,129

CLUTCH FOR A BRACE Filed July 26, 1952 rates atent Office 2,850,129Patented Sept. 2, 1958 CLUTCH FOR A BRACE Porter S. Morgan, Westport,Conn., assignor to I. 'L.

This invention relates to bit stocks or braces, and more particularly tosuch devices in which unidirectional clutch means are provided, as forinstance by a ratchet.

An object of the invention is to provide an improved brace having aunidirectional drive or ratchet action associated with the chuck, whichis characterized by virtually no back drag.

Another object of the invention is to provide an improved brace having aunidirectional drive associated with the clutch, which is characterizedby virtually no lost motion.

A still further object of the invention is to provide an improved bracehaving unidirectional drive associated with the chuck, which ischaracterized by a continuous or smooth gripping action as distinguishedfrom an intermittent or stepped action.

Still another object of the invention is to provide an improved braceaccording to the foregoing, in which the unidirectional clutch actionmay be easily and quickly made to operate in either of reversedirections.

A feature of the invention is the provision of an improved brace asabove set forth, which is simple and sturdy in its construction andreliable in use, being constructed of relatively few parts and beingeconomical to fabricate.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure 1 is a side elevational view of an improved brace made inaccordance with the invention.

Fig. '2 is a fragmentary horizontal section, enlarged, taken on line 2-2of Fig. 1.

Fig. 3 is a fragmentary vertical section taken on line 33 of Fig. 2.

Fig. 4 is a fragmentary vertical section taken approximately on line 44of Fig. 2, the locking members being shown in elevation.

Fig. 5 is a view partly in elevation and partly in vertical sectiontaken on line 55 of Fig. 3.

Fig. 6 is a view like Fig. 4, but reduced in size and showing the partsin position to effect a unidirectional drive.

Referring to Fig. 1 the improved brace of this invention comprises ahandle or frame part 10 formed with the usual crank shape, having at oneend a kob 11 and, on the crank portion a hand grip 12. At its other endthe handle part 10 has the usual type of chuck 13 adapted .to mount bitsand the like.

In accordance with the present invention an improved, stepless,smooth-acting unidirectional clutch mechanism is provided between thechuck 13 and the handle part 10, enabling the brace to be used in themanner of a ratchet brace but without back drag or lost motion beingpresent. The improved unidirectional drive is further characterized byan advantageous stepless action, by few and simple parts, and byconvenience of operation.

Referring to Figs. 1, 2 and 3, this improved drive comprises a casing orfitting 14 which I hereinafter term .a pin 17 passing through said part.

- with the fitting 14.

an angle fitting, in which the chuck 13 is rotatably mounted and towhich the handle part 10 is rigidly secured. The angle fitting 14comprises a body having a laterally extending portion 15 provided with abore 16 in which the handle part 10 is secured, as by means of The anglefitting 1 has a main body portion 18 which is somewhat barrel-like inits shape, having a vertical bore 19 extending completely through it.

The chuck 13 has a shank or shaft 20 which is preferably provided withknurling 21, and which has an annular groove 22 intermediate its ends.On the knurled portions 21 of the shaft 20 spur gears 23 are carried,

meshing with a pinion gear 24 rotatable in a small vertical bore 25 inthe body portion 18 of the fitting, ,Fig. 2.

Theshank or shaft 20 is retained in the fitting 141by a crescent-shapedmember 26 which is received in the groove 22 of the shaft, said memberbeing secured to the fitting 14 as by drive pins 27.

Top and bottom plates 28 and 29 respectively are carried .by the fitting14, enclosing the shaft 20, gears Y23 and pinion .24, the bottom platehaving an opening 30 through which the shaft 20 extends. As shown in.Fig. .3 the fitting .14, at its upper and lower portions, is

preferably laid over the top and bottom plates 28 and .29 to securethese in place.

The top plate 28 is provided with a depressed portion 31 forengagementwith the end of the shaft 30 to act as a thrust bearing therefor. 1

To effect aunidirectional clutch or braking action I provide a frictionbrake wheel '32 which is carried by and rotatable with the pinion 24.The brake wheel '32 may have a bore conforming to the cross sectionalshape .of the pinion .24 to enable the pinion to be passed force whichis-applied to the brake wheel 32 will result in the chuck 13 tending tolock and therefore to turn I preferablymake the gears 23 ofsubstantially larger pitch diameter than the pinion 24, and make thefriction brake whee1.32 of larger diameter than the pinion '24, and thusobtain a desirable mechanical advantage whereby a relatively smallbraking force applied to the brake wheel 32 will result in a muchgreater force beingrequired on the chuck 13 if it is to be turned withrespect to the fitting 14.

For the purpose of selectively unidirectionally locking the brake wheel32 against movement in one direction or the other I provide lockingmembers 34 in the lateral extension 15 of the fitting 14, said membersbeingpreferably substantially cylindrical in shape and being carried ina cylindrical bore 35 which extends horizontally in the extension 15 andcommunicates with the clearance spaces 33 of the fitting. The lockingmembers 34 have bores 34a accommodating a helical compression spring 34bby which they are yieldably urged apart or away from each other, andsaid members have milled cuts 37 providing braking surfaces forengagement with the periphery of the brake wheel 32. The locking members34 are normally held in closely spacpd or juxtaposed positions as shownin Fig. 2, wherein the braking surfaces thereof are engageable with theperiphery of the brake wheel 32, by a collar 36 which is rotatable onthe extension 15 of the fitting and which encircles the locking members34.

Referring to Figs. 4 and 6 the collar 36 has a portion of its borerelieved, providing a clearance space 38 having camming surfaces 39 atits ends. The purpose of this clearance space is to enable one or theother of the locking members to be moved outward by the spring 34b,thereby to disengage the brake wheel 32 and relinquish all controlthereover.

As shown in Fig. 6 the collar 36 has been shifted counterclockwise fromthe position of Fig. 4, resulting in the rightmost locking member 34shifting outward to separate its brake surface from the brake wheel 32.

A detent means is provided in conjunction with the collar 36, saiddetent means comprising the pin 17, comprising notches 40 in the outeredge of the collar 36, and comprising a concave-convex spring washer 41disposed between the collar and the body portion of the fitting. It willbe understood that this detent means will retain the collar 36 in eitherof three positions in which it is placed. One such position is shown inFigs. 2 and 4, wherein both of the locking members 34 are broughtsubstantially in contact with the brake wheel 32. Another position ofthe collar 36 is shown in Fig. 6, wherein the rightmost locking membermay occupy an outwardly shifted position. The third position of thecollar 36 is opposite to that shown in Fig. 6, and enables the leftmostlocking member 34 to occupy an outwardly shifted position.

The braking action on the brake wheel 32 is effected as follows: Whenthe collar 36 is in the position shown in Figs. 2 and 4, the brakesurfaces 37 of the locking members 34 will be engageable with spacedpoints on the periphery of the brake wheel 32, which points define asmall arc of said periphery. The brake wheel will also engage the shaft20, or more properly the bottom of the groove 22 in the shaft 20, andthis point of engagement will be directly opposite the are bounded bythe points of engagement of the brake wheel with the locking members 34.A wedging action is thus obtained, and if for example the shaft 20should experience clockwise turning force with respect to the fitting14, as viewed in Fig. 2, it will because of the meshing engagement ofthe gears shift the brake wheel 32 downward and wedge the wheel betweenthe shaft 20 and the lower of the two brake members 34. counterclockwiseturning applied to the shaft 20 will in a similar manner result in thebrake wheel 32 being shifted upward and being wedged between the shaft20 and the upper of the two locking members 34. Thus the chuck 13 willbe locked to the handle part against relative rotation in both direc-'If new the collar 36 should be turned in one tions. direction or theother it will enable one or the other of the locking members 34 to beshifted away from the locking wheel 32, to disengage the latter. If, forexample, the lower of the two locking members 34, as seen in Fig. 2, isshifted out of engagement with the locking wheel 32 the said wheel willbe permitted to have free counterclockwise rotation at all times,allowing the shaft as viewed in Fig. 2 to have free clockwise rotation.Any clockwise turning force exerted on the shaft 20 will tend to shiftthe pinion 24 and brake wheel 32 downward and maintain the brake wheelout of wedging engagement with the shaft 20 and the upper of the lockingmembers 34. Opposite turning force exerted on the shaft 20 will howeverimmediately shift the pinion 34 and brake wheel 32 upward, causing thewheel to be wedged between the shaft 20 and the upper of the two lockingmembers. Thus a unidirectional clutch action is obtained, and I havefound that such action is highly desirable in a tool of the characterdescribed in that there is practically no lost motion involved at anytime, inasmuch as the shifting movement experienced by the pinion 24 andbrake wheel 32 is extremely slight. Moreover, when one or the other ofthe locking members 34 is in its outward orreleasing position, freeturning of the brake wheel and pinion is permitted in the one directionwithout restraint, and accordingly no back drag is experienced in theoperation of the brake. Thus when starting a hole with the bit,particularly if it is a small size bit, there will be no necessity tohold the chuck 13 against retrograde movement it the ratchet action isbeing utilized. Moreover, where space is limited, the present improvedunidirectional clutch mechanism is advantageous in the elimination of astepped movement such as is characteristic of a ratchet device havingteeth. Often when employing a ratchet device in a limited space, part ofthe movement of the handle is lost be cause the click or pawl cannot bemade to pass the next tooth of the ratchet wheel. This, however, is notexperienced when using the brace of the invention, inasmuch as there iscomplete absence of any stepped movement in the unidirectional drive.

The bearing for the shaft 20 in the fitting 14 is provided by theengagement of the crests of the teeth of the gears 23 with the bore 19.Likewise engagement of the pinion 24 with the bore 25 providessufiicient bearing for the pinion and the brake wheel 32.

I prefer to effect the assembly of the device as follows: With the partsall disassembled, the bottom plate 29 is assembled and secured to thefitting 14. The brake wheel 32 is then slipped into the bore 19 from thetop and shifted edgewise into the clearance spaces 33 provided in theextension 15. The brake wheel is shifted until it passes into thetransverse bore 35 as far as it will go. The shaft 20 is passed upthrough the bottom plate 29, and the lower gear 23 pressed on the shaft.The crescent-shaped retainer member 26 is then put in place and securedby the drive pins 27. The upper gear 23 is then pressed on the shaft 20,the pinion 24 dropped into place, passing through the brake wheel 32,whereupon the top plate 28 is positioned and secured to the fitting 14.The locking members 34 may then be inserted in the bore 35, togetherwith the spring 36. The washer 41 and collar 36 are placed on theextension 15, the handle part 10 inserted in the extension 15 and thepin 17 driven into place.

Variations and modifications may be made within the scope of the claimsand portions of the improvements may be used without others.

I claim:

1. A unidirectional drive mechanism for use in a brace or the like,comprising a turnable driving part; a shaft which is to be driven,rotatably mounted on said driving part; a friction brake wheel rotatablymounted on the driving part; a driving connection between the shaft andbrake wheel, causing turning of the wheel when the shaft is turned withrespect to said driving part; normally operative releasable frictionbraking means to lock the friction wheel against turning solely in onedirection; and manually operable means for rendering said braking meansinoperative, thereby to provide for free turning of the brake wheel insaid one direction, said driving connection comprising step-up gearingbetween the shaft and the brake wheel causing angular movements of thelatter to be greater than those of the shaft.

2. The invention as defined in claim 1 in which the braking meansincludes a portion of said shaft, having a surface engageable with thefriction wheel, said shaft portion when engaged under pressure tendingto lock the wheel against turning.

3. The invention as defined in claim 1 in which the driving connectionincludes a large gear secured to the driven shaft, and a small gearsecured to the brake wheel and meshing with the large gear, and in whichthe brake Wheel is of larger diameter than the small gear, providing amechanical advantage in the transmission of force to the driven shaftwhen braking force is applied to the brake wheel.

4. In combination, a handle part; a driven member rotatably mounted onsaid part; a friction brake wheel rotatably mounted on said part; amechanical advantage stepup gear driving connection between the drivenmember and brake wheel, causing turning of the wheel when the handlepart is turned with respect to the driven member but at a greaterangular speed; normally operative releasable friction braking means tolock the friction wheel against turning in one direction; normallyoperative releasable friction braking means to lock the friction wheelagainst turning in the other direction; and manually operable means forselectively rendering inoperative one or the other of said brakingmeans, thereby to selectively provide for free turning of the brakewheel in one direction or the other and Wedging of the wheel againstturning in the opposite direction.

5. The invention as defined in claim 4 in which the braking meansinclude a pair of aligned members movable on said handle part toward andaway from each other along a path generally tangential to said brakewheel, said members having brake surfaces engageable with said wheel,and in which the manually operable means includes a rotatable collar onthe handle part, extending around the aligned members and having cammeans engageable with the members to control the positions thereof. 7

6. In a device of the character described, an angle fitting; a drivenmember rotatably mounted on the fitting; a first gear within thefitting, secured to the driven member to turn therewith; a second gearrotatable in the fitting, meshing with the first gear; a friction brakewheel secured to the second gear to turn therewith when the drivenmember is turned with respect to the fitting; a

pair of members having brake surfaces for engagement with the brakewheel, said members being movable in the fitting between operativepositions wherein the brake surfaces thereof engage adjacent points onthe periphery of the brake wheel bounding a small arc, and positionswherein they disengage the wheel; means providing a brake surface in thefitting for engagement with the periphery of the brake wheel opposite tothe said bounded are, enabling said wheel to be wedged between saidmeans and either of said members to prevent its rotation; and manuallyoperable means for selectively holding one or the other of said membersin its operative position, thereby to selectively provide for freeturning of the brake wheel in one direction or the other and wedging ofthe wheel against turning in the opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS803,669 Cook Nov. 7, 1905 1,090,578 Smythe Mar. 17, 1928 1,388,836Ripsch et al Aug. 23, 1921 1,816,295 Pitter July 28, 1931 1,845,667Johnson Feb. 16, 1932 2,331,339 Morris Oct. 12, 1943 2,539,861 RobinsonJan. 30, 1951 2,578,686 Fish Dec. 18, 1951 FOREIGN PATENTS 635,153France Mar. 9, 1928

